Last Modified: Friday, September 07, 2012 8:54 PM
DERIDDER — An FBI agent on Thursday outlined the movements of Billie Joe Weldon and Kimberly Ann Stephens, or at least their cell phones, on Aug. 23, 2009, the day Stephens is believed to have been killed.
Weldon is on trial for second-degree murder in 36th Judicial District Court in Beauregard Parish in the death of the 27-year-old Stephens, whose bruised and bloodied body was found in a vacant lot off Granberry Road on Aug. 26, 2009.
Weldon and Stephens were in an extramarital relationship at the time of her death, both prosecutors and the defense counsel have said.
William C. Williams of the FBI, an expert in cell phone analysis, showed the similarities in the travels of Weldon’s and Stephens’ cell phones throughout the day of the slaying. He was careful to point out in his analysis, though, that he had know way of knowing who was using those cell phones.
Williams said every time a cell phone sends or receives a text or phone call, it communicates with the dominant cell tower in its area. Through those communications, a cell phone can be traced to a general area. Giving an exact location, though, is impossible, he said.
Those communications are recorded by cell phone companies, he said.
The southeast triangular sector of the AT&T cell phone tower on Butler Road services the Granberry Road area, as well as the address at which Stephens was living at the time of her death, Williams testified.
Between 1:15 p.m. and 2:15 p.m. on Aug. 23, 2009, Stephens and Weldon exchanged 62 text messages — most of Stephens’ went through the Butler Road cell tower, while Weldon’s phone was communicating through a tower near Starks, Williams said.
Weldon’s phone pinged the Butler Road tower at around 2:15 p.m., Williams said.
He said the cell records then indicate that both phones were in the area south of Kisatchie Forest, near Pitkin, from around 3 p.m. until after 6 p.m.
He then went through a timeline of pings off cell towers that their cell phones communicated with at similar times throughout that afternoon. Those towers were below Kisatchie Forest near Pitkin, DeRidder, Slaydonville, Singer and back to Slaytonville and DeRidder.
Nothing was sent from Stephens’ phone after 8:14 p.m., and her phone communicated with a tower, for an incoming text message, for the last time at 8:32 p.m., he said.
He also detailed how Weldon’s phone later pinged off towers in Orange, Texas.
During cross-examination, defense attorney David Wallace pointed out that Weldon’s phone communicated with the north sector of the Butler Road tower at 8:38 p.m., six minutes after Stephens’ phone’s last logged communication.
Wallace’s cross-examination with Williams was at times testy, with Wallace pressing the FBI agent on how large an area the cell tower services.
Williams said he didn’t know for certain.
Mark Begnaud, a radio frequency engineer for AT&T, testified he had integrated and designed the tower.
He said it could cover up to 6 to 8 miles, or until it reached a “handoff” point with another tower.
Williams also said that on Aug. 23, Stephens’ cell phone logged a new identification number, indicating that its SIM card had been changed.
The court earlier Thursday heard a discussion on whether to allow the testimony of Williams and Begnaud and a slide provided by Williams that showed where the southeast sector of the Butler Road tower is dominant.